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Why does my car alarm keep going off?

Charlotte Phillips, 3 months ago

3 min read

  • Advice
Car alarm repair image

WhoCanFixMyCar troubleshoots some of the possible reasons why your car alarm might be going off, what you should do in this scenario, and who to contact to fix the problem.

Can your car alarm go off by itself?

Yes, unfortunately. Your car alarm can go off by itself for a number of reasons, and you definitely want to get this annoying problem fixed as soon as possible. Not only is it a rather annoying sound to hear for you and the people around you, it could also indicate something in your car is not quite working as it should be.

Your car alarm going off by itself could be triggered by a number of different things, and sometimes you won’t be able to resolve this problem yourself. The best course of action is to find a car alarm repairs specialist who can diagnose the problem for you, and get that jarring sound to stop!

Contents guide:

Low car battery

Wiring problems

Dead key fob battery

Faulty door lock sensor

Doors not closed properly


Why would your car alarm go off randomly?

Your car alarm can go off randomly for a number of different potential reasons.

Low car battery

A low battery level teamed with your car alarm going off by itself is a big indication that there’s something wrong with your car battery. Commonly unknown by drivers, one of the main functions of your car’s alarm system is to indicate to you that your battery is low, and you probably should get this checked out.

You can quite confidently pinpoint this as the culprit when you try to start your engine and your car alarm starts to ring out. If this happens, you should check the voltage of your battery with a voltmeter and, if it’s lower than specified in your owner's manual, be sure to take it to the garage so a specialist can check your battery or fit you a new one.


Wiring problems

Sometimes when your car alarm is going off randomly it can be triggered by problems with your electric wiring. It could be that the electrics are faulty or have somehow become disconnected all together, but you can attempt to troubleshoot if this is the issue by looking for other symptoms.

For example, you may also notice that your headlights are flashing or your car horn is blaring without you pressing it; these are all potential signs that your car alarm wiring has been disrupted in some way.


Dead key fob battery

Your key fob contains a radio transmitter that sends a signal to your car’s receiver unit to lock or unlock the vehicle when you press it. Over time, your key fob can become damaged and cause the transmitter signal to stop working. When this becomes faulty, the signal cannot be sent to the receiver, sometimes causing the car alarm to go off by itself.


Faulty door lock sensor

Your car alarm also monitors your door locks to make sure that nobody is trying to enter your car. If your door lock sensor is faulty, it could ultimately be triggering the car alarm to go off randomly when falsely sensing that the doors are being opened. This can be tricky to diagnose yourself, so the best course of action is to take your car to a specialist auto locksmith who can fix the problem for you.


Doors not closed properly

Similarly, not having your car doors closed properly could be tricking your car into thinking that the door lock sensor has been triggered, causing your alarm system to go off. If you ever notice that your car alarm is going off at night, it could well be that you have simply not closed your doors properly.


How to stop your car alarm going off

You can try some of the following steps to stop your car alarm from going off, depending on exactly what the issue is:

1. Lock and unlock the driver’s side door with the key - You may be able to shut off the alarm by unlocking the door with the correct car key because this can send a signal to the alarm system that the correct key has been used.

2. Start the car - Because your car alarm is used to prevent the car from being stolen from someone without a key, using the key to start the car can reset the alarm.

3. Read your owner’s manual - Some cars have a more complicated process for shutting off the alarm system. The best thing to do if you’re not sure is to read your owner’s manual. 

How you stop your car alarm from going off really depends on the issue at hand. It could be as simple as going and checking all of your doors are closed properly, or you may need more specialist assistance if you’re faced with the problem of faulty sensors or wiring.


Either way, you can be sure to find a qualified specialist in our network of over 15,000 garages here at WhoCanFixMyCar, who will be able to resolve your car alarm issues for you.

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